Benzaldehyde Selectivity Research Articles

MnCo2O4and CoMn2O4octahedral nanocrystals synthesized via a one-step co-precipitation process and their catalytic properties in benzyl alcohol oxidation

Most of the present synthetic strategies for spinel oxides rely on high-temperature processes such as hydro-/solvothermal treatments and calcination. Herein, we succeeded in synthesizing two Mn–Co mixed spinel oxides via a facile one-step co-precipitation approach. The obtained MnCo2O4 and CoMn2O4 octahedral nanocrystals were enclosed by {111} and {101} facets, respectively. Redox couples of Mn2+/Mn3+ and Co2+/Co3+ coexisted in both products. The concentration of the reactants, the manner of addition of alkali and the introduction of chloride ions could affect their crystallographic phase or particle size. A dissolution–crystallization process was deemed to be involved in their formation. Their catalytic activities were evaluated by using typical samples of MnCo2O4 (MCo1) and CoMn2O4 (CMn1) as catalysts in the aerobic oxidation of benzyl alcohol. Conversions of 82.3% and 34.1% were attained for MCo1 and CMn1, respectively. Meanwhile, a 100% selectivity for benzaldehyde was achieved for both samples during the whole reaction period. The catalytic reaction in our case proceeded through the Mars–van Krevelen mechanism. The better catalytic performance of MCo1 than that of CMn1 could be mainly ascribed to the higher content of available trivalent cations and lattice oxygens on the exposed {111} planes and their sub-layers. The high selectivity might be derived from the optimal bond strength of these two oxides as well as the mild reaction conditions we designed. Balancing activity and selectivity, our synthesized Mn–Co spinel oxides were effective and competitive in the selective oxidation of benzyl alcohol.

Vapor Phase Oxidation of Benzyl Alcohol over Nano Au/SBA-15 Catalysts: Effect of Preparation Methods

Au/SBA-15 nano catalysts were synthesized from four different methods, viz., homogeneous deposition–precipitation, micro-emulsion, impregnation and polyol, and their catalytic activities were investigated for the vapor phase oxidation of benzyl alcohol to benzaldehyde. The physico-chemical properties of the catalysts were characterised by XRD, TEM, BET surface area, pore size distribution, CO-chemisorption and XPS techniques. The structural data of the catalysts along with their catalytic studies indicate that the presence of very small metallic Au0 species with particle size of 7–8 nm, was responsible for the higher activity observed in the vapor phase oxidation of benzyl alcohol reaction. The title reaction, though industrially important, was used as a test reaction to investigate firstly, the influence of different preparation methods on the uniform dispersion of gold particles on the support SBA-15 and to understand the metal-support interaction in Au/SBA-15 catalysts, and secondly, to study the catalytic performance of the catalyst (Au/SBA-15) in terms of activity, selectivity and stability over a period of reaction time. The conversion of benzyl alcohol was found to increase with decrease in the size of gold particles. Smaller gold particles with higher percentage of dispersion on the support SBA-15 had a beneficial effect on the catalytic activity. Among the four methods used for the preparation of gold on SBA-15 support, the catalyst prepared by homogeneous deposition–precipitation method showed the best performance in terms of conversion, selectivity for benzaldehyde and longer catalyst life. Vapor phase oxidation of benzyl alcohol over nano Au/SBA-15 catalysts.

Synthesis and Catalytic Performance of Al-MCM-48 and Ti-MCM-48

Mesoporous sieves MCM-48 with hetero atom were synthesized by adding aluminum and titanium sources through hydrothermal method. The results showed that MCM-48 could be synthesized respectively by adjusting exactly the alkalinity of synthesis gel. The conversion rate of DIPB on Al-MCM-48 increased to 80% after 9 h and the selectivity of IPB was 97%. The conversion rate of styrene on Ti-MCM-48 increased to 9% after 8 h and the selectivity of benzaldehyde was 85%. The available active sites, which were introduced by aluminum and titanium atoms, were effectively utilized for catalyst reaction due to the presence of mesopores in Al-MCM-48 and Ti-MCM-48.

A New Method for Immobilization of NDHPI on SBA-15 Carrier Used as Catalyst for Selective Oxidation of Toluene

Mesoporous molecular sieve SBA-15 immobilized N,N-dihydroxypyromellitimide (NDHPI) was prepared by a new method, which was realized through the coupling NDHPI with pre-grafted glycidoxypropyl chains of glycidoxypropyl-SBA-15. SBA-15 immobilized N-hydroxyphthalimide (NHPI) by impregnation method was also prepared for comparison. The two catalysts were characterized by Fourier transform infrared spectroscopy, N2 adsorption–desorption technique, thermogravimetric analyses, X-ray diffraction, scanning electron microscope, transmission electron microscope and X-ray photoelectron spectroscopy. Then the catalysts and N,N-bis(salicylidene) ethylenediiminocobalt (Cosalen) complex were used into oxidation of toluene with molecular oxygen. The more active and reusable catalyst was the immobilized one coupled by NDHPI with glycidoxypropyl-SBA-15, which improved the total selectivity of benzaldehyde and benzyl alcohol to 46.0 % with the conversion of toluene 14.8 % at 90 °C for 7 h. Mesoporous molecular sieve SBA-15 immobilized N,N-dihydroxypyromellitimide (NDHPI) was prepared by a new method, which was realized through the coupling NDHPI with pre-grafted glycidoxypropyl chains of glycidoxypropyl-SBA-15. SBA-15 immobilized NHPI by impregnation method was also prepared for comparison. Their structure was characterized and their catalytic performance combined with Cosalen complex in the molecule oxidation of toluene were compared. Their reusability performance was also discussed.

Copper, copper oxide nanoparticles and copper complexes supported on mesoporous SBA-15 as catalysts in the selective oxidation of benzyl alcohol in aqueous phase

Copper(II) complexes, copper and copper oxide nanoparticles supported on SBA-15 have been prepared and their catalytic performance in benzyl alcohol oxidation in aqueous phase studied. Hybrid mesoporous SBA-15 functionalized with imidazole ionic liquid and functionalized with an amino alcohol chelate ligand have been used as solid supports in order to tether copper(II) complexes. From these materials, copper nanoparticles and copper oxide nanoparticles supported on SBA-15 have also been synthesized. Copper based materials have been characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), N2 adsorption-desorption, transmission electron microscopy (TEM) with microanalysis by energy-dispersive X-ray (EDX), solid-state nuclear magnetic resonance spectroscopy (CP-MAS-NMR), Fourier-transform infrared spectroscopy (FT-IR), UV–vis diffuse reflectance spectroscopy (DRUV-vis), thermogravimetric analysis (TG-DTG) and electrochemical techniques. The catalyst synthesized by immobilization of ionic liquid containing copper and followed by chemical reduction method showed the highest activity in the oxidation of benzyl alcohol with a 73% conversion and 54% selectivity of benzaldehyde (30 min reaction time). The stability of the catalysts has been also examined by voltammetry measurements.

Bimetallic synergistic Au/CuO-hydroxyapatite catalyst for aerobic oxidation of alcohols

A catalyst consisting of Au supported on copper oxide-modified hydroxyapatite (Au/CuO-HAP) was prepared using a homogeneous deposition-precipitation method. The catalyst was characterized using atomic absorption spectrometry, N2 adsorption-desorption, powder X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The catalytic performance in liquid-phase aerobic oxidation of alcohols was investigated. The catalytic activity and benzaldehyde selectivity in benzyl alcohol oxidation with the bimetallic Au/CuO-HAP catalyst were significantly better than those with monometallic Au/HAP and CuO-HAP catalysts. The conversion of benzyl alcohol and selectivity for benzaldehyde at 120 °C for 1.5 h under aerobic oxidation conditions were 99.7% and 98.4%, respectively. Various aromatic alcohols were selectively converted to their corresponding aldehydes or ketones over Au/CuO-HAP. The Au/CuO-HAP catalyst could be reused at least four times without loss of activity.

Effectively photocatalytic aerobic oxidation of benzyl alcohol catalyzed by spinel Co–Ni ferrite under visible light irradiation

Magnetic ferrite Co x Ni1−x Fe2O4 (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0) nanocrystalline complex oxides were prepared by sol–gel auto-combustion method and well characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, diffuse reflectance UV–visible spectroscopy and N2 adsorption–desorption analysis. The catalytic performances of the as-prepared samples were evaluated in photocatalytic oxidation of benzyl alcohol using molecular oxygen as oxidant under visible light irradiation. The results have shown that the catalysts exhibit remarkably high activities in the photocatalytic oxidation of benzyl alcohol. In particular, 18.9 % of benzyl alcohol conversion and 90.1 % of selectivity for benzaldehyde were obtained when the sample Co0.3Ni0.7Fe2O4 was used as catalyst under optimum conditions. The catalyst could be magnetically separated easily for reuse, and no obvious loss of activity was observed when reused in six consecutive runs. Spinel Co–Ni ferrites were prepared by a facile, mild and environment-friendly route. The catalysts exhibit remarkably high activities in the photocatalytic oxidation of benzyl alcohol under visible light irradiation. The catalyst can be magnetically separated easily and has shown prominent recyclability.

Synthesis of hierarchical ZSM-5 hexagonal cubes and their catalytic activity in the solvent-free selective oxidation of toluene

In the present work, ZSM-5 with hexagonal cubic morphology was successfully synthesized by the hydrothermal method in the presence of tetrapropylammonium hydroxide and nonionic surfactant as mesopore template. The structural, textural, morphological and thermal properties of the as-synthesized zeolite samples were evaluated by XRD, XRF, FT-IR, N2 adsorption, HR-TEM, HR-SEM and TGA. The powder X-ray diffraction and FT-IR analysis confirms the formation of pure ZSM-5 zeolite without any impurities present. The surface area analysis showed that the mesoporous surface area was evidently increased without intensively destroying the microporosity in the surfactant-assisted zeolite. The catalytic performance of the ZSM-5 zeolites was evaluated in the liquid phase selective oxidation of toluene using tert-butyl hydroperoxide as an oxidant. The surfactant-assisted ZSM-5 shows a higher toluene conversion and benzaldehyde selectivity at optimum conditions.

Characterization and catalytic reactivity of mordenite – Investigation of selective oxidation of benzyl alcohol

Commercial mordenite was dealuminated with hydrochloric acid by refluxing at 373K for different durations to develop a stable catalyst for the selective oxidation of benzyl alcohol. The commercial and dealuminated mordenite samples were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FTIR) spectroscopy, N2 adsorption–desorption, high resolution scanning electron microscopy (HR-SEM) and temperature programmed desorption (NH3-TPD). The results revealed that the external surface area increased with acid treatment while preserving the mordenite structure. The catalytic performance of acid-treated mordenite was evaluated in the selective oxidation of benzyl alcohol with tert-butyl hydroperoxide (TBHP) as the oxidant and acetonitrile as the solvent. The influences of the variation in catalyst amount, reaction temperature, TBHP/BzOH ratio and SiO2/Al2O3 ratio (SAR) were investigated. The sample with a SAR of 33, obtained after acid treatment for 3h, exhibited a higher conversion than the other samples. At the optimum conditions, the benzyl alcohol conversion and benzaldehyde selectivity were about 99% and 98%, respectively, over this sample. This catalyst could be reused at least four times without any significant loss in its activity and selectivity. The selective oxidation of substituted benzyl alcohols is also reported.

General Strategy for Preparation of Carbon-Nanotube-Supported Nanocatalysts with Hollow Cavities and Mesoporous Shells

Hollow-structured mesoporous catalysts (HMCs) that comprise catalytically active cores, interior reaction space, and permeable shell(s), can bring new opportunities for high-efficiency catalysis. Nevertheless, all the existing HMCs are limited to small spherical yolk–shell type configuration (i.e., zero-dimensional (0D) structure). To include more active cores and to add new merits to the HMCs, in this work, we report a general strategy for preparation of complex one-dimensional (1D) HMCs, in which carbon nanotubes (CNTs) serve as a backbone to support catalytic components and mesoporous silica and/or microporous metal–organic frameworks (MOFs; e.g., ZIF-8) or transition-metal oxides (e.g., Nb2O5) act as membrane-like shells for molecular screening, catalyst protection, and surface functionality. Several types of catalytic nanoparticles (e.g., noble metals Au, Pd, and Au–Pd alloy; and transition metal oxides Co3O4, ZnO, and TiO2) have been anchored onto the CNTs and encapsulated or sheathed with the mesoporous silica shell. Concerning their workability, we have further tested the CNT-based HMCs for selective oxidation of benzyl alcohol to benzaldehyde. Intriguingly, both shell porosity and interior space of catalysts exert significant impacts on benzyl alcohol conversion, benzaldehyde selectivity, and the catalyst longevity. Conceptually, such 1D HMCs can be viewed as linearly integrated 0D HMCs, but they can significantly include more catalytic nanoparticles and enhance catalyst–support interaction, which adds another dimension for the design and synthesis of HMCs.

Effects of Biomolecules on the Selectivity of Biosynthesized Pd/MgO Catalyst toward Selective Oxidation of Benzyl Alcohol

Catalysts prepared through biosynthesis have aroused wide concern recently, but the detailed role of biomolecules and the identification of the main components have not been figured out yet. In this study, biogenic Pd/MgO catalysts were prepared through sol-immobilization (SI) and absorption-reduction (AR) methods, respectively, using Artocarpus heterophyllus Lam leaves extracts as reductant and stabilizer. The catalyst prepared by SI method showed obviously higher benzaldehyde selectivity than that by AR method under the same conditions. The difference can be attributed to the different oxidation behaviors of phenolic hydroxyls between the two synthetic procedures. In the SI procedure, the phenolic hydroxyls were oxidized to semiquinone, while in the AR procedure, the phenolic hydroxyls were oxidized to hydroxyquinone, resulting in less carboxyls binding onto the surface of the Pd nanoparticles (NPs), thus inhibiting the formation of the byproducts. Moreover, gallic acid, chlorgenic acid, and rutin were ...

Synthesis of cobalt-containing mesoporous catalysts using the ultrasonic-assisted “pH-adjusting” method: Importance of cobalt species in styrene oxidation

Cobalt-containing SBA-15 and MCM-41 (Co-SBA-15 and Co-MCM-41) mesoporous catalysts were prepared via ultrasonic-assisted “pH-adjusting” technique in this study. Their physiochemical structures were comprehensively characterized and correlated with catalytic activity in oxidation of styrene. The nature of cobalt species depended on the type of mesoporous silica as well as pH values. The different catalytic performance between Co-SBA-15 and Co-MCM-41 catalysts originated from cobalt species. Cobalt species were homogenously incorporated into the siliceous framework of Co-SBA-15 in single-site Co(II) state, while Co3O4 particles were loaded on Co-MCM-41 catalysts. The styrene oxidation tests showed that the single-site Co(II) state was more beneficial to the catalytic oxidation of styrene. The higher styrene conversion and benzaldehyde selectivity over Co-SBA-15 catalysts were mainly attributed to single-site Co(II) state incorporated into the framework of SBA-15. The highest conversion of styrene (34.7%) with benzaldehyde selectivity of 88.2% was obtained over Co-SBA-15 catalyst prepared at pH of 7.5, at the mole ratio of 1:1 (styrene to H2O2) at 70°C.

Catalytic oxidation of styrene to benzaldehyde over a copper Schiff-base/SBA-15 catalyst

The amino-modified mesoporous material SBA-15 (NH2-SBA-15) was prepared via co-condensation of tetraethylorthosilicate with 3-aminopropyltriethoxysilane in the presence of an amphiphilic triblock copolymer as a pore-directing agent under acidic conditions. The SBA-15-supported Cu Schiff-base complex (Cu-SBA-15) was then synthesized by condensation of salicylaldehyde with NH2-SBA-15, followed by the addition of a solution of Cu(NO3)2. The supported complex was systematically characterized by elemental analysis, inductive coupled high frequency plasma atomic emission spectrometry, powder X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, field scanning electron microscopy, transmission electron microscopy, N2 absorption-desorption, and thermo gravimetric analysis, and was used as the catalyst for the selective oxidation of styrene to benzaldehyde. The influence of the reaction parameters was assessed. The maximum conversion of styrene was 84.4% and the selectivity for benzaldehyde was 83.9%, when the reaction was conducted with a 2:1 molar ratio of H2O2:styrene in the presence of 3.8 wt% catalyst at 100 °C for 8 h. The TOF was 261.1 h−1, and the catalyst could be used three times without significant loss of activity. The uniformly sized pore channels, high specific surface area, and well-distributed active centers of the catalyst may contribute to the high activity.

Effect of Acetic Anhydride on the Oxidation of Toluene to Benzaldehyde with Metal/Bromide Catalysts

Acetic anhydride (AA) was used as specific additive for liquid-phase oxidation of toluene in acetic acid to weaken the corrosivity of reaction system and increase the yield of benzaldehyde by using Co/Mn/Br catalyst system and 1,1,2,2-tetrabromoethane as bromine sources. The effect of AA on the liquid-phase oxidation of toluene to benzaldehyde was carefully studied. It was found that adding a certain amount of AA in acetic acid caused different reaction process from the reaction in pure acetic acid. Noticeably, addition of AA could increase both the selectivity of benzaldehyde and conversion of toluene during 2–8 h, whereas in pure acetic acid, benzaldehyde selectivity gradually dropped with a rise in toluene conversion. AA could greatly decrease water content in the reaction system, possibly reduce the corrosivity of substrates, and increase the toluene conversion. However, too much AA could cause the deactivation of the catalyst. By optimizing conditions, the maximum selectivity and yield of benzaldehyd...

Highly selective oxidation of benzyl alcohol to benzaldehyde catalyzed by nano Au/γ-Al2O3 under environment-friendly conditions

The liquid phase oxidation of benzyl alcohol to benzaldehyde under environment-friendly conditions has been investigated. Water is used as a medium to replace toxic organic solvents. The reaction used hydrogen peroxide as the oxidant. The novel green reaction was catalyzed by nano Au/γ-Al2O3. Gold nanoparticles supported on gamma alumina (γ-Al2O3) were prepared by a deposition–precipitation method. These synthesized materials were characterized by several techniques such as X-ray diffraction, N2 low temperature adsorption, and transmission electron microscopy. The benzaldehyde selectivity changed depending on the supports, the Au loading and the reaction temperature. Over 98 % selectivity of benzaldehyde was observed at 60 °C after 2 h on the 2 % Au supported on γ-Al2O3 which was calcined at 550 °C.

Preparation of silver–tungsten nanostructure materials for selective oxidation of toluene to benzaldehyde with hydrogen peroxide

We have developed a facile one-pot synthetic strategy to prepare Ag/WO3 nanostructure materials with different morphologies using a cationic surfactant, cetyltrimethylammonium bromide. These materials were employed as catalysts in the direct synthesis of toluene to benzaldehyde using H2O2. The morphology of the Ag/WO3 materials can be varied by changing the synthesis parameters. The size and shape of the Ag/WO3 nanostructure catalyst has direct influence on the toluene conversion and benzaldehyde selectivity. The effect of different reaction parameters like reaction temperature, H2O2 to toluene molar ratio, reaction time, and so forth have been studied in detail. The Ag/WO3 catalyst with ∼7 nm silver nanoparticles on the WO3 nanorod with a diameter ∼60 nm showed the best catalytic activity of 42% toluene conversion with 93% benzaldehyde selectivity. The catalyst did not show any leaching up to four reuses, showing the true heterogeneity of the catalyst.

A simple aloe vera plant-extracted microwave and conventional combustion synthesis: Morphological, optical, magnetic and catalytic properties of CoFe2O4 nanostructures

Nanocrystalline magnetic spinel CoFe2O4 was synthesized by a simple microwave combustion method (MCM) using ferric nitrate, cobalt nitrate and Aloe vera plant extracted solution. For the comparative study, it was also prepared by a conventional combustion method (CCM). Powder X-ray diffraction, energy dispersive X-ray and selected-area electron diffraction results indicate that the as-synthesized samples have only single-phase spinel structure with high crystallinity and without the presence of other phase impurities. The crystal structure and morphology of the powders were revealed by high resolution scanning electron microscopy and transmission electron microscopy, show that the MCM products of CoFe2O4 samples contain sphere-like nanoparticles (SNPs), whereas the CCM method of samples consist of flake-like nanoplatelets (FNPs). The band gap of the samples was determined by UV–Visible diffuse reflectance and photoluminescence spectroscopy. The magnetization (Ms) results showed a ferromagnetic behavior of the CoFe2O4 nanostructures. The Ms value of CoFe2O4-SNPs is higher i.e. 77.62emu/g than CoFe2O4-FNPs (25.46emu/g). The higher Ms value of the sample suggest that the MCM technique is suitable for preparing high quality nanostructures for magnetic applications. Both the samples were successfully tested as catalysts for the conversion of benzyl alcohol. The resulting spinel ferrites were highly selective for the oxidation of benzyl alcohol and exhibit important difference among their activities. It was found that CoFe2O4-SNPs catalyst show the best performance, whereby 99.5% selectivity of benzaldehyde was achieved at close to 93.2% conversion.

Effects of Oxygen Transfer Limitation and Kinetic Control on Biomimetic Catalytic Oxidation of Toluene

Under oxygen transfer limitation and kinetic control, liquid-phase catalytic oxidation of toluene over metalloporphyrin was studied. An improved technique of measuring dissolved oxygen levels for gas-liquid reaction at the elevated temperature and pressure was used to take the sequential data in the oxidation of toluene catalyzed by metalloporphyrin. By this technique the corresponding control step of toluene oxidation could be obtained by varying reaction conditions. When the partial pressure of oxygen in the feed is lower than or equal to 0.070 MPa at 463 K, the oxidation of toluene would be controlled by oxygen transfer, otherwise the reaction would be controlled by kinetics. The effects of both oxygen transfer and kinetic control on the toluene conversion and the selectivity of benzaldehyde and benzyl alcohol in biomimetic catalytic oxidation of toluene were systematically investigated. Three conclusions have been made from the experimental results. Firstly, under the oxygen transfer limitation the toluene conversion is lower than that under kinetic control at the same oxidation conditions. Secondly, under the oxygen transfer limitation the total selectivity of benzaldehyde and benzyl alcohol is lower than that under kinetic control with the same conversion of toluene. Finally, under the kinetics control the oxidation rate of toluene is zero-order with respect to oxygen. The experimental results are identical with the biomimetic catalytic mechanism of toluene oxidation over metalloporphyrins.

Improvement of catalytic activity in selective oxidation of styrene with H2O2 over spinel Mg–Cu ferrite hollow spheres in water

Uniform spinel Mg–Cu ferrite hollow spheres were prepared using carbon spheres as templates. For comparison, solid Mg–Cu ferrite nanocrystals were also prepared by sol–gel auto-combustion, hydrothermal and coprecipitation methods. All the samples were characterized by Fourier transform infrared spectrophotometry (FT-IR), X-ray diffractometry (XRD), transmission electron microscopy (TEM) and N2 physisorption. The samples were found to be efficient catalysts for oxidation of styrene using hydrogen peroxide as oxidant. Especially, in the case of Mg0.5Cu0.5Fe2O4 hollow spheres, obvious improvement on catalytic activity was observed, and 21.2% of styrene conversion and 75.2% of selectivity for benzaldehyde were obtained at 80°C for 6h reaction in water. The catalyst can be magnetically separated easily for reuse and no obvious loss of activity was observed when reused in six consecutive runs.

Synthesis and Characterization of Tungstophosphoric Acid/Pentaethylenehexamine/ZrSBA‐15 and Its Use in the Selective Oxidation of Benzyl Alcohol under Solvent‐Free Conditions

AbstractA layer‐by‐layer deposition strategy was employed for the immobilization of tungstophosphoric acid (HPW) onto a pentaethylenehexamine (PEHA)‐grafted ZrSBA‐15 framework to a give HPW/PEHA/ZrSBA‐15 composite. The resulting composite was characterized by XRD, SEM, TEM, FTIR, thermogravimetric analysis, N2 sorption, and X‐ray photoelectron spectroscopy, and these methods showed that the composite was stable in polar environments. These properties were attributed to the method of preparation, which ensured that a dense and stable array of HPW was encapsulated within the pores of PEHA‐modified ZrSBA‐15. In the H2O2‐mediated oxidation of benzyl alcohol, the 25 % HPW/PEHA/ZrSBA‐15 catalyst exhibited high selectivity (>99 %) for benzaldehyde. Moreover, the oxidation reaction was performed under solvent‐free conditions, and the catalyst was recycled several times with negligible loss in selectivity and conversion. This HPW‐based catalyst was also efficient at selectively oxidizing other benzylic and alkyl alcohols to the corresponding aldehydes.